I think the code is less interesting then the (graphic) design and some of the wording (kharma) that people are used to. And maybe further expressions like AITA or /r/whathever. How is the legal situation here I wonder
The old code that reddit published says you have to put a copyright on any service that runs the software, so /r/foo would be fine, and the bottom of each page would say something like “Portions of server software copyright reddit 2017”.
I am not a lawyer, but that’s my reading of the license on that repo.